Dual source parenteral infusion apparatus

ABSTRACT

A dual parenteral solution apparatus for delivering predetermined volumes of two solutions at predetermined flow rates with increased accuracy. The apparatus has a shut-off valve in the supplementary solution supply system which is immediately activated when the supplemental solution supply is depleted.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an apparatus for administering parenteralsolutions to medical patients. In particular, this application isdirected to an improved apparatus for delivering precise volumes ofsolutions at precise rates from more than one solution source.

2. Description of the Prior Art

Infusion delivery systems for delivering liquid to a patient from morethan one solution source have been previously known. The most commonsystems use gravity flow and manually adjustable tubing clamps or pinchvalves. They may employ a variety fo valves and junctions to controlflow at the desired rate and sequence. Examples of such systems aredescribed in U.S. Pat. Nos. 3,886,937; 4,034,754; 4,114,617; 4,219,022;4,223,695; 4,236,515; 4,237,879; 4,237,880; 4,250,879; 4,252,116;4,256,104; 4,256,105; and 4,258,712. Dual delivery systems relying onelectronic flow control means are described in U.S. Pat. No. 4,094,318,for example.

Automatic flow control systems relying on a drop counter which measuresthe frequency of drop fall through a drip chamber have been previouslyknown. In general, a light beam from a lamp to a light detector ispositioned so that it is interrupted by drops falling through a dripchamber. The frequency of the breaking of the light beam and/or the timelapse between drops breaking the light beam are directly proportional tothe flow rate and are used to determine adjustments to be made to a flowcontrol valve to change flow to the desired rate. Examples of systemscomprising drop counters and control systems responsive thereto aredescribed in U.S. Pat. Nos. 3,163,179; 3,601,124; 3,886,937; 4,038,982;4,314,567.

The prior art systems do not provide the precise control of the totaldelivered volume of small quantities of secondary solutions which can beobtained with the apparatus of this invention.

SUMMARY AND OBJECTS OF THE INVENTION

It is an object of this invention to provide a system which can provideprecise volumes of primary and secondary solutions to a patient atprecise flow rates.

The parenteral infusion apparatus of this invention for deliveringparenteral solutions from two sources comprises a first drip chamberwith a primary flow sensor means associated therewith for detectingliquid flow rate through the primary drip chamber and a supplementalsolution drip chamber with supplemental solution flow sensor meansassociated therewith for detecting liquid flow rate through thesupplemental solution drip chamber. The outlet of the supplementalsolution drip chamber is connected with the primary drip chamber inletby conduit means having a shut-off control system means associatedtherewith. The shut-off control system includes means for terminatingsupplemental solution flow through the conduit when the measured flowdetected in the supplemental solution drip chamber is less than the flowdetected in the primary drip chamber.

The apparatus of this invention is particularly useful when thesupplemental solution or secondary drip chamber and the supplementalsolution or secondary solution source associated therewith is remotefrom the controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of the dual source parenteralinfusion apparatus of this invention.

FIG. 2 is a cross-sectional view of a drip chamber and drop sensorcombination of this invention.

FIG. 3 is a cross-sectional view of an alternate embodiment of asupplemental solution drip chamber and drop sensor combination with afiber optics light sensor.

FIG. 4 is an isometric view of the drop sensor embodiment with a fiberoptics light sensor.

DETAILED DESCRIPTION OF THE INVENTION

The parenteral administration of medical liquids to patients is aroutine, long established practice. Aqueous solutions of amino acids,dextrose, electrolytes and saline are commonly administered to patientsover prolonged periods of time. Frequently, the patient must beadministered a supplemental solution. Preferably, this supplementalsolution is administered through the same hypodermic needle to avoidunnecessary pain and the trauma to the patient of additional punctures.To avoid dilution and incompatibility problems, it is also preferredthat the flow of the primary solution be temporarily interrupted duringadministration of the secondary solution. After administration of thesecondary fluid is completed, flow of the primary liquid is resumed.

Both fluids are usually supplied to the patient by gravity flow. Thesecondary fluid source is maintained at a higher elevation than theprimary solution source, and the secondary fluid supply is thereforerelatively more remote from the primary liquid source and controller. Asa consequence, the connective tubing leading from the supplemental fluidsource systems is frequently much longer and has a greater internalvolume than other tubing in the system.

The supplemental supply system is primed by squeezing sidewalls of thesupplemental drip chamber together with the supplemental drip chamberoutlet conduit being pinched closed. Air is expelled from the dripchamber into the supplemental solution container. As the drip chambersidewalls return to their original shape, liquid is drawn from thesupplemental solution container into the drip chamber, preferably to alevel at about the middle of the drip chamber. The supplemental dripchamber outlet conduit is then opened, permitting supplemental solutionto enter the drip chamber and an equal volume to pass through the dripchamber outlet conduit. When the air has been displaced from the outletconduit, it is connected to the primary solution supply conduit,typically through a "Y" connection or junction. The supplementalsolution supply conduit is usually primed with a standard, large volumeparenteral solution.

Routine administration of small, precise volumes of solutions such asantibiotics, tranquilizers, cardiovascular drugs and the like assupplemental solutions to an established primary parenteral solutionadministration apparatus has not been practical prior to this invention.A substantial proportion of supplemental solution may be required tofill the tubing, particularly if a small volume of supplemental solutionis to be administered. Usually the supplemental solution isreconstituted by adding water to the vial containing moisture-free drug.The dried contents are precise, but the volume of water added may beapproximate. To accurately administer drug to the patient, therefore, isis necessary to completely empty the supplemental solution container orvial. This frequently draws air into the supplemental solution dripchamber and into the outlet conduit leading therefrom. Air trapped inthe outlet conduit can be removed only by disconnecting the supplementalsystem and repriming it. This problem is solved by the apparatus of thisinvention.

Referring to FIG. 1, a schematic representation of the dual sourceparenteral infusion delivery apparatus is illustrated. The primarysolution container 2 is connected through connective tubing 4 to thecheck valve 6. Connective tubing 8 leads from the check valve 6 to the"Y"-junction 10. The outlet of the junction 10 is connected with theprimary drip chamber 14 by connective tubing 12. The controller 16 has adrop sensor 18 and precision flow control valve 20. The drop sensor 18counts the drops and measures the drop rate. This correlates directly tothe flow rate, and the valve 20 is adjusted to correct for any variancefrom the desired flow rate. Connective tubing 22 leads from the controlvalve 20 to the patient.

The supplementary solution container 24 is supported at a higherelevation than the primary solution container 2, and a supplementarysolution drip chamber 26 is provided immediately below the secondarysolution container to minimize the internal volume of connecting tubingor other connecting elements. Secondary drop sensor 28 is a means forcounting drops falling through the secondary drip chamber 26. Connectingtubing 30 leading from the drip chamber 26 passes through an on-offpinch valve 32 of the controller 16 and then to the supplementarysolution inlet of the junction 10. Connecting cable 34 leads to thecontroller 16 from the supplementary drop sensor 28. Cable 34 is used toprovide light or electric lighting power to the supplemental solutiondrop sensor 28. It also transmits light or electrical signals producedin response to falling drops or drop counts corresponding thereto fromthe supplementary solution drop sensor 28 as will be described inconjunction with a description of the drop sensors shown in FIG. 2-4.

While flow of supplementary solution continues through drip chamber 26,tubing 30, junction 10, tubing 12 and drip chamber 14, drop counts indrip chambers 26 and 14 are the same. However, when the supplementarysolution is depleted, drop fall in the drip chamber 26 will decline andstop while flow of residual solution in drip chamber 26 and tubing 34will continue. In the apparatus of this invention, if the drop countsupplementary solution as measured in drip chamber 26 falls below thedrop count measured in drip chamber 14, the pinch valve 32 immediatelycloses, terminating further solution flow from the drip chamber 26through conduit 30. The back pressure on the check valve 6 is thenreduced, and the check valve opens, reinitiating primary solution flowthrough the "Y"-junction 10. Subsequent administration of thesupplementary solution will begin and end with almost identical levelsof supplementary solution in drip chamber 26 since significant air flowinto drip chamber 26 is prevented. This permits very precise solutionadministration. With prior art systems, air intrusion into conduit 30would have occurred, requiring repriming and inaccurate administrationsince an unpredictable and underdetermined amount of supplementarysolution would remain in the connecting tubing.

Referring to FIG. 2, a cross-sectional representation of a drip chamberand a drop sensor assembly comprising a lamp light source and a lightsensor combination are shown. The drip chamber 40 is of standardconstruction having transparent and flexible plastic sidewalls 42. Thesize of the orifice 46 in the drop former 44 determines the size of thedroplets formed. The falling drops impinge on the anti-splash element48, reducing air-liquid mixing. A constant liquid level 50 is maintainedin the drip chamber 40 to prevent passage of air from the drip chamber40 to the outlet conduit 52.

Light from the lamp 54 mounted in housing 55 passes through a concavelens 56 and as a parallel beam passes through the walls 42, impinging onthe convex lens 58 which focus the transmitted light on the light sensor60, creating a voltage between light sensor electrical leads (notshown). Interruption of the light beam passing between the lamp 54 andlight detector 60 by passage of falling drops therethrough causes anabrupt change in the electrical voltage which can be easily detected andcounted by conventional systems known in the art. Each interruptioncorresponds to the passage of a drop. Both the primary drop detector 18and supplemental drop detector 28 in the apparatus of FIG. 1 can beconstructed as shown in FIG. 2.

Because the supplementary solution drop detector is remote from thecontroller, electrical wire leads from the light sensor to thecontroller can be a source of extraneous electrical signals (noise). Itis therefore desired to construct the drop detector and output signaltransmission system therefore in such a manner that signal interferencefrom extraneous sources is eliminated during transmission to thecontroller or its effects minimized.

In one embodiment, the light signal generated by the light detector 60is amplified by conventional means prior to transmission to thecontroller so that the comparative magnitude of the desired signal isfar greater than the interfering signals and the noise effect is notsignificant.

FIGS. 3 and 4 are directed to an alternative embodiment of thesupplementary solution drop detector employing fiber optics. In thissystem, transmitted light is conducted to a light sensor in thecontroller by means of the fiber optics cable, and extraneous electricalinterference arising during transmission is eliminated. The drop chamber70, drop former 72 and anti-splash element 74, are the same as describedabove with respect to FIG. 2. The liquid level 76 is maintained byterminating fluid flow when the differential drop rates are detected.Supplementary solution is introduced through conduit 78 and is removedthrough outlet tubing 80. In this embodiment, however, the lightoriginating from the lamp 84 in the housing 82, after passing throughthe concave lens 86 and drip chamber walls 87, is focused by convex lens88 on the end 90 of the fiber optics cable 92. The fiber optics cable 92has a terminal male connector 94 which connects with the correspondingreceptor socket recess 96 in housing 82. Light emitted at the other endof the fiber optics cable is sensed by a light sensor in the controllerin a conventional manner. The light deflection occasioned by the passageof a drop through the supplemental solution drip chamber effects anelectrical signal deflection from the light detector in the same manneras described above with regard to the embodiment in FIG. 2.

FIG. 4 is an isometric view of the light sensor housing 82 showing therelative locations of the lamp 84, the jack connector 98 of the electriccable 100 for the lamp 84, the fiber optics cable 92 and connector 94.

The invention claimed is:
 1. A parenteral infusion apparatus fordelivering parenteral solutions from two sources comprising a first dripchamber with a primary flow sensor means associated therewith fordetecting liquid flow rate through the primary drip chamber, asupplemental solution drip chamber with supplemental solution flowsensor means associated therewith for detecting liquid flow rate throughthe supplemental solution drip chamber, the outlet of the supplementalsolution drip chamber being connected with the primary drip chamberinlet by conduit means having a shut-off control system means associatedtherewith for terminating supplemental solution flow through the conduitwhen the measured flow detected in the supplemental solution dripchamber is less than the flow detected in the primary drip chamber. 2.The parenteral infusion apparatus of claim 1 wherein the supplementalsolution drip chamber is remote from the primary drip chamber.
 3. Theparenteral infusion apparatus of claim 1 wherein the flow sensor meansis a means for detecting passage of individual drops falling through thesupplemental solution drip chamber.
 4. The parenteral infusion apparatusof claim 3 wherein the supplemental solution flow sensor means comprisesa light source for directing light through the path of drops falling inthe supplemental solution drip chamber and a light collector means forfocusing light transmitted through the supplemental solution dripchamber.
 5. The parenteral infusion apparatus of claim 4 wherein thelight is focused on a light sensor.
 6. The parenteral infusion apparatusof claim 5 wherein the electrical signal from the light sensor isamplified and transmitted to a controller.
 7. The parenteral infusionapparatus of claim 4 wherein the light is focused on the end of a fiberoptics cable in optical communication with a light sensor means in acontroller.
 8. Ther parenteral infusion apparatus of claim 4 wherein thelight source is a light-emitting diode. .Iadd.
 9. A parenteral infusionapparatus for delivering parenteral solutions from two sourcescomprising:a primary solution source; a first conduit means forconducting solution supplied by said primary solution source; a checkvalve located in said first conduit means; a supplementary solutionsource; a second conduit means for conducting solution supplied by saidsupplementary solution source; an outlet conduit leading to a patientsite; a junction means for connecting said first conduit means and saidsecond conduit means to said outlet conduit; wherein the flow path ofsaid primary solution includes said first conduit means, said checkvalve, said junction means, and said outlet conduit, and the flow pathof said supplementary solution includes said second conduit means, saidjunction means, and said outlet conduit; controller means, engaging saidsecond conduit means, and including means for selectively occluding saidsecond conduit means to terminate solution flow from said supplementarysolution source, and further including a flow control valve meansengaging said outlet conduit for controlling the flow therethrough; andprimary flow sensor means located in said primary solution flow path fordetecting the liquid flow rate of solution therethrough, andsupplementary flow sensor means located in said supplementary solutionflow path between said supplementary solution source and said engagementof said second conduit means with said controller means for detectingthe liquid flow rate of solution therethrough, wherein said controllermeans is responsive to said flow sensor means for controlling saidselectively occluding means and said flow control valve means. .Iaddend..Iadd.
 10. The parenteral infusion apparatus of claim 9, wherein saidcontroller means for selectively occluding said second conduit meanscomprises a pinch valve engaging said second conduit means. .Iaddend..Iadd.
 11. The parenteral infusion apparatus of claim 10, wherein saidjunction means comprises a "Y" connection. .Iaddend. .Iadd.12. Theparenteral infusion apparatus of claim 11, wherein said check valve isclosed when said supplementary solution is flowing through said secondconduit means, and said check valve opens in response to a reduction inback pressure when said second conduit means is occluded. .Iaddend..Iadd.13. The parenteral infusion apparatus of claim 12, wherein saidprimary flow sensor means includes a drop sensor opposing a dripchamber. .Iaddend. .Iadd.14. The parenteral infusion apparatus of claim13, wherein said supplementary flow sensor means is connected to saidsecond conduit means. .Iaddend. .Iadd.15. The parenteral infusionapparatus of claim 14, wherein said supplementary flow sensor meansincludes a second drop sensor opposing a second drip chamber connectedto said outlet conduit. .Iaddend. .Iadd.16. A parenteral infusionapparatus for delivering parenteral solutions from two sourcescomprising:first tubing for delivering a primary solution; second tubingfor delivering a supplementary solution; connective tubing leading to apatient site; means for connecting said first tubing and said secondtubing to said connective tubing; wherein the flow path of said primarysolution includes said first tubing, said connecting means, and saidconnective tubing, and the flow path of said supplementary solutionincludes said second tubing, said connecting means, and said connectivetubing; means, located in said flow path of said primary solution, foralternately allowing primary solution or supplementary solution to flowthrough said connective tubing; and a controller, including means,located in said primary solution flow path, for sensing the flow ofsolution therethrough, and means, connected to said second tubing, forsensing the flow of said supplementary solution, and having a pinchvalve for selectively occluding said second tubing and a flow controlvalve for adjusting the flow rate through said connective tubing..Iaddend. .Iadd.17. A parenteral infusion apparatus for deliveringparenteral solutions from two sources comprising: first conduit meansfor delivering a primary solution; second conduit means for delivering asupplementary solution; connective tubing leading to a patient site;means for connecting said first conduit means and said second conduitmeans to said connective tubing; a controller, including first sensormeans for detecting liquid flow through said second conduit means,second sensor means for detecting liquid flow through said connectivetubing, means, responsive to said first sensor, for selectivelyoccluding said second conduit means, and means, responsive to saidsecond sensor means, for adjusting the flow rate through said connectivetubing; and means, in fluid connection with said first conduit means,for alternately allowing primary solution or supplementary solution toflow through said connective tubing. .Iaddend. .Iadd.18. A parenteralinfusion apparatus for delivering parenteral solutions from two sourcescomprising:a first conduit for delivering a primary solution; a secondconduit for delivering a supplementary solution and having a first flowsensor associated therewith; a third conduit having a second flow sensorassociated therewith; a controller including a first valve engaging saidsecond conduit and a flow control valve; means for connecting saidfirst, second and third conduits to said flow control valve; and means,in fluid connection with said first conduit, for alternately allowingprimary solution or supplementary solution to flow to said flow controlvalve, wherein said controller is responsive to said first flow sensorfor selectively occluding said second conduit and is responsive to saidsecond flow sensor for adjusting said flow control valve. .Iaddend.